21331386 has 12 divisors (see below), whose sum is σ = 46218042. Its totient is φ = 7110456.

The previous prime is 21331369. The next prime is 21331399. The reversal of 21331386 is 68313312.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 20875761 + 455625 = 4569^2 + 675^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 592521 + ... + 592556.

Almost surely, 2^21331386 is an apocalyptic number.

21331386 is an abundant number, since it is smaller than the sum of its proper divisors (24886656).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21331386 is a wasteful number, since it uses less digits than its factorization.

21331386 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1185085 (or 1185082 counting only the distinct ones).

The product of its digits is 2592, while the sum is 27.

The square root of 21331386 is about 4618.5913436891. The cubic root of 21331386 is about 277.3360706990.

Adding to 21331386 its reverse (68313312), we get a palindrome (89644698).

The spelling of 21331386 in words is "twenty-one million, three hundred thirty-one thousand, three hundred eighty-six".